Class: WorkerPlugins::QueryLinksStatus

Inherits:
ApplicationService show all
Defined in:
app/services/worker_plugins/query_links_status.rb

Instance Method Summary collapse

Methods inherited from ApplicationService

#db_now_value, #mysql?, #postgres?, #quote, #quote_column, #quote_table, #relation_unscoped?, #sqlite?

Instance Method Details

#count_linked_rows ⇒ Object 



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# File 'app/services/worker_plugins/query_links_status.rb', line 16

def count_linked_rows
  base_scope = workplace.workplace_links.where(resource_type: query.klass.name)

  # When the query applies no scoping, the original `resource_id IN (SELECT
  # DISTINCT <target_table>.id FROM <target_table>)` subquery materialized
  # every row of the target model just to count — 2+ seconds on a 340k-row
  # target. We drop the DISTINCT subquery and instead `INNER JOIN` the
  # target table on its primary key so the composite index on links drives
  # the scan and each matching link does a cheap PK probe to confirm the
  # target row still exists. Orphaned links (whose target has since been
  # deleted) are correctly excluded from the count, so `checked_count`
  # never exceeds `query_count`.
  return base_scope.joins(unscoped_target_join_sql).count if relation_unscoped?(query)

  base_scope.where(resource_id: query_with_selected_ids).count
end

#perform ⇒ Object 



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# File 'app/services/worker_plugins/query_links_status.rb', line 4

def perform
  query_count = query.count
  checked_count = count_linked_rows

  succeed!(
    all_checked: query_count == checked_count,
    checked_count:,
    query_count:,
    some_checked: checked_count.positive? && checked_count < query_count
  )
end

#query_with_selected_ids ⇒ Object 



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# File 'app/services/worker_plugins/query_links_status.rb', line 59

def query_with_selected_ids
  WorkerPlugins::SelectColumnWithTypeCast.execute!(
    column_name_to_select: query.klass.primary_key,
    column_to_compare_with: WorkerPlugins::WorkplaceLink.column_for_attribute(:resource_id),
    query: query.distinct
  )
end

#resource_id_expression_for_join(resource_id_column) ⇒ Object

On MySQL / MariaDB and SQLite, implicit conversion handles comparing the target’s primary key against the VARCHAR ‘resource_id` column. Postgres is strict about types and needs an explicit cast when they differ.



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# File 'app/services/worker_plugins/query_links_status.rb', line 44

def resource_id_expression_for_join(resource_id_column)
  return resource_id_column unless postgres?

  target_pk_type = query.klass.column_for_attribute(query.klass.primary_key).type
  resource_id_type = WorkerPlugins::WorkplaceLink.column_for_attribute(:resource_id).type

  return resource_id_column if target_pk_type == resource_id_type

  case target_pk_type
  when :uuid then "CAST(#{resource_id_column} AS UUID)"
  when :integer then "CAST(#{resource_id_column} AS BIGINT)"
  else resource_id_column
  end
end

#unscoped_target_join_sql ⇒ Object 



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# File 'app/services/worker_plugins/query_links_status.rb', line 33

def unscoped_target_join_sql
  target_table = quote_table(query.klass.table_name)
  target_pk = "#{target_table}.#{quote_column(query.klass.primary_key)}"
  resource_id_column = "#{quote_table(WorkerPlugins::WorkplaceLink.table_name)}.#{quote_column(:resource_id)}"

  "INNER JOIN #{target_table} ON #{target_pk} = #{resource_id_expression_for_join(resource_id_column)}"
end